1. Technical Field
The present invention relates to an electronic device and an image processing apparatus including a power line communication function.
2. Background Art
A multiple function image forming apparatus (which may be simply called multiple function apparatus or MFP (Multi Function Peripheral)) including various image processing functions containing a facsimile function, a printer function, a copy function, and a scanner function can be used as a communication apparatus, an image processing apparatus, an image output unit, or the like. Since consecutive use of the functions is a rare case, a multiple function apparatus become widespread (for example, refer to JP-A-2005-33829).
The multiple function apparatus generally has a standby state in which the corresponding function can operate immediately when an external signal or operation from an operation unit is input, and a sleep state in which although immediate operation is impossible, when an external signal or operation from an operation unit is input, a transition is made to an operable state and then the operation corresponding to the external signal input or operation input from the operation unit is performed.
In the standby state, power is supplied to all units of the multiple function apparatus and when the external signal or operation from the operation unit is input, immediately the corresponding function can be executed. In the sleep state, power is supplied to a unit for detecting external signal input or operation input from the operation unit and for controlling to supply power to all units of the multiple function apparatus (for example, a circuit board for implementing a main control unit) and power supply to a circuit board for performing any other control, a printer unit, a scanner unit, etc., is stopped. Therefore, power consumption of the multiple function apparatus can be decreased.
However, the main control unit to which power is supplied even in the sleep mode generally has a function of controlling the whole multiple function apparatus and thus power consumption of the hardware unit (circuit board, etc.,) for implementing the main control unit is large; if power is supplied at all times, considerable power is supplied. This is not limited to the multiple function apparatus and also applies to a general electronic device wherein power supply is changed between the standby state and the sleep state.
Power line communications are communications using a power line for supply commercial power as a transmission path and when power line communications are conducted, communications are conducted among various electronic devices through a power line communication modem connected to a power supply socket. An electronic device incorporating the function of a power line communication modem is also proposed (for example, refer to JP-A-2005-143026). In such an electronic device, power supply to the electronic device and communications through a power line are made possible simply by connecting a power supply plug to a power supply socket. Also in such an electronic device having the power line communication function, if power supply is changed between the standby state and the sleep state, likewise power needs to be supplied to a main control unit at all times.